I know you said earlier that you're sure you have the arms on the correct sides, but just how sure are you? If they were swapped, would the holes then line up? The part numbers could be wrong from side to side. I had that happen once on a Mustang. They had the inner and outer water pump gasket numbers reversed, so every supplier kept send the wrong gasket.

Each lower control arm has a welded bracket on one side as a stopper, its definitely the correct one.